docs: def _find_unused_static_warnings(filename, lines, ast_list):
      """Warn about unused static variables."""
      static_declarations = dict(_get_static_declarations(ast_list))
  
      def find_variables_use(body):
          for child in body:
              if child.name in static_declarations:
                  static_use_counts[child.name] += 1
  
      static_use_counts = collections.Counter()
      for node in ast_list:
          if isinstance(node, ast.Function) and node.body:
              find_variables_use(node.body)
          elif isinstance(node, ast.Class) and node.body:
              for child in node.body:
                  if isinstance(child, ast.Function) and child.body:
                      find_variables_use(child.body)
  
      count = 0
      for (name, _) in sorted(static_declarations.items(),
                              key=lambda x: x[1].start):
          if not static_use_counts[name]:
              print("{}:{}: unused variable '{}'".format(
                  filename,
                  lines.get_line_number(static_declarations[name].start),
                  name))
              count += 1
  
      return count